1. Field of the Invention
This invention relates to a screwable pressure actuated operating cylinder with closure elements for closing the cylinder tube, which can be employed to produce translational movement of mechanisms in the field of fluidic energy transmission utilizing flowing media (liquids, gases) as pressure media, where this operating cylinder is particular suitable for high pressure aggressive media.
2. Prior Art
Screwable pressure medium actuated operating cylinders in accordance with German patent DE OS 19 215 43 are known, in particular hydraulic differential or plunger pistons, whose cylinder tube, capable of accepting one piston, is provided with closure elements provided at the lower or head end. These closure elements are screwed up over the outer thread of the cylinder tube, and closed securely against leaks via a ring seal located on the inner thread.
Furthermore, screwable operating cylinders are known in accordance with patent EP 060 17 36 A 1, where the thread carrying the closure elements is arranged in the inner shell of the cylinder tube and where sealing is achieved via sealing elements. At the same time, screwable operating cylinders having cylinder tube inner-, or cylinder tube-outer threads are known, in which sealing is achieved by means of an elastomer seal, which is located in the ring face of the cylinder tube or, also, as described in German patent DE 35 17 137 A 1, as a face seal of the guide closure element.
All known screwable operating cylinders always achieve cylinder tube sealing by the insertion of elastomer sealing elements.
In these embodiments the frequency of faults developing in the high pressure range as well as the complicated and therefore expensive metal-cutting required in manufacture.
Pressure medium-actuated linear motors in threaded embodiments necessitate highly developed manufacturing technology and are therefore expensive to manufacture. Nevertheless, they can only be used to a limited extent, especially in the aggressive high pressure range. If the components of the operating cylinder are coated, in order to make them resistant against aggressive media, additional costs arise for the manufacture of the joining elements, which also remain prone to frequent faults due to the effect of high pressure substances.
Known technical solutions require highly skilled personnel for manufacture of the individual components of the operating cylinder, so that the manufacturing costs for known technical solutions are high.